Adjustable light source for photographic printing machines



May 12, 1931. I s, HOPKINS 1,804Q771 ADJUSTABLE LIGHT SOURCE FORPHOTOGRAPHIC PRINTING MACHINES Filed Oct. 22. 1929 Patented May 12, 1931UNITED STATES PATENT OFFICE ROY S. HOPKINS, OF ROCHESTER, NEW YORK,ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, ACORIfQRATION OF NEW YORK ADJUSTABLE LIGHT SOURCE PHOTQGRAPHIC PRINTINGMACHINES Application filed Qctober 22, 1929. Serial No. 401,407.

This invention relates to photography, and more particularly to a sourceof light for photographic printing machines.

It has for its object to provide a source of light from which light raysof different known intensities may be obtained with minimum effort onthe part of an operator. Another object is to provide a source of lighthaving a plurality of light intensities which may be used one at a time.Another object of my invention is to provide a multiple light sourcewhich is adjustable to bring a single source of light into operativeposition at a time and to permit other sources of light of differentintensities to be operatively positioned for printing. Another object ofmy invention is to provide a source of light ncluding a movable basehaving a plurality of lamp receptacles arranged to accurately positionthe filaments of each-lamp in a print ing position. Still anotherobj-ect is to pro vide a pivoted base having-a plurality of lampsockets, each socket being adapted to make a circuit when swung into anoperative printing posit-ion. Still another object is to provide asource oflight havinga plurality of sockets movably mounted and meansfor automatically making a circuit through any one socket positioned forprinting. I

Other objects will appearfrom the following specifi'catiomthe novelfeatures being pointed-out in the claims at the end thereof.

Coming now to the drawings, wherein like characters denote like partsthroughout 1 F ig. 1 is a diagrammatic side elevation of V a printerhaving a portion of its side broken away, showing in elevation a detailof my invention. 7 t

Fig. 2- is a front elevation of the lamp bracket supporting a. pluralityof lamp sockets. I 1 Fig. 3 isa front elevation of the contact block.

'F 1 is a detail in section of a spr ng contact and the contact block;

modification of a lamp bracket supporting a embodiment of my invention.

My present invention is particularly adapted for use in a printingmachine of the type shown in my copending application, Serial No.158,882, filed December 10, 1926 although obviously it may be used withother type of machines. For the operation of the printer parts,reference may be had to the showing in my copending application.

As shown in Fig. 1, a printer 1, is provided with a source of lightcomprising a plurality of lamps 2, which are supported by a bracket 3.The bracket 3 also supports a block 41 which carries a plurality ofcontact points with which the spring contact 6 completes a circuit. Thespring contact 6 is supported. by an insulated block 7, which is mountedwith bracket 3 on the bolt 8, said bolt acting as a pivot for thebracket. A reflector 9 is provided to direct the light rays through theaperture 10 to the mirror 11 which directs said light rays to theprinting panel of the printer 1, as fully described in my copendingapplication above referred to.

The bracket 3 as best shown in Fig. 2. comprises a base 12. pivoted onthe bolt- 8. and a plurality of lamp sockets for lamps of differentintensities. For example one socket also supports a contact block 4carrying a plurality of contact buttons 18 one connected to each lampsocket as by wires 19 with wires QO-leading to a'source of power 21, asshown in Fig. 5.

The contact button 18-and the contact point 22'of spring contact 6 maybe of any desired form, but the nipple and dimple types as shown in Fig.3 and Fig. 4 are preferred. \Vhen contact point 22enters a dimple 18 itboth makes a circuit and acts as a snap-latch for holding bracket 3 in aset position.

A modification of bracket 3'is shown in Fig. 6, comprising a base 23,pivotally mounted at 17. supportinga plurality of lamp sockets 24. saidlamp sockets being adjustably mounted as by thumb screw 25, saidadjustment, pro

' bracket supporting vsaid lamps and insulate, ing block.

printing machine due to the density oithe individual negatives. To dothis, by the present method, he must reduce the current to the lamp by arheostat, which method has a number of disadvantages. First, the rangeof light intensities can not always be taken care of by'a rheostat.Second, a change in the rheostat does not produce an lnstantaneouschange in lamp brilliance. Third, a color change in theilluminationtakes place in altering lamp intensities through a wide range by. arheostat.

By the method disclosed in my invention, however, these ditiiculties areavoided as the operator is merely required to change from one lamp toanother by swinging the pivotally mounted bracket for major changes inlight intensity, and the operator may use a rheostat for minor changesin light intensity. Thus much unnecessary heat is avoided, the light canbe more accurately controlled, and much less current is consumed,

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a photographic printing machine the combination with a printingpanel, of a source v of light for said printing panel comprising; aplurality of lamps and a pivotal base sup porting said lamps,

2.;111 a photographic printing machine the combinatlon with a printingpanel," of. an adjustable source of 7 light for said-printing j panelcomprismg a plural ty of-lamps, eachlam) having a different intensitvand a pivotally mounted bracket support-ing said lamps.

3. In a the combination with-a printing panel, of

5 an adjustable source of licht'for said panel comprising a plurality oflamps, each lamp having a different intensity, an insulatingblockcarrying a plurality oi contact points,

and a pivotally mounted bracket supporting. said lamps andinsulatingblock; I

4. In aphotographic printing machine the combination with a printingpanel, of an adjustablesource of light for said panel comprising aplurality of lamps of diiierent intensities, an insulating blockcarrying a plurality-jot contact points,each point connected to thecorresponding lamp socket, a spring contact to complete any one ol theplurality of lamp circuits,-and-a pivotally mounted 5. In a photographicprinting machine the photographic printing machine, I

combination with a printing panel, of an adjustable source oflight forsaid panel com- 7 prising a plurality of lamps of different intensities,an insulating block of fibrous mate rial carrying a plurality of contactpolnts, each point connected to the correspondlng lamp socket, a springcontact, completing any one of the plurality of lamp circuits, mountedon an insulated ,base, a pivotal bracket supporting said lamps andinsulating contact point block and-a pivot support-: ing said bracketand insulated spring contact base.v I

6. In a photographic printing machine of the type utilizing aconcentrated light source, the combination with a printing panel of apivotally mounted lamp bracket supporting for sail bracket, aninsulating otal support block supporting a series of contact pointscarried by the bracket, each contact point being connected to alamp,,and means to simul taneously bring one point at a time intooperative position with a spring contact, and the correspondinglamp-into operative position for illuminating the printing panel, saidspring contact being adapted to hold the bracket in said position;

7 In a photographic printing machine the combination with a printingpanel a source of light for said printing-panel comprising a pluralityof. adjustable lamp sockets and pivotal base supporting said lamps' 8.In a photagraphio printing machine the combination with a printingpanel, an adustable source of li ht for said printing panel comprising aplurality of lamps,r.each lamp having a different intensity,apluralityof radially adjustable lamp sockets supporting said lamps, anda pivotal bracket supporting 'said'bracket. I a

* 9." In a photographic printingmachine the combination with a printingpanel of an ad 'justablesource of light "for said panel comprising-aplurality or lamps, each lamp having a different intensity, a'pluralityofradially 'adjustablelamp sockets supporting said lamps,2aninsulating block carryinga plu-- rality of contact points, and a pivotalbracket" supporting said bracket and insulating block,

10. In a photographic printing machine the combination with a printingpanel, of an i adjustable: source oflightfor said panel comprising aplurality of lamps of difierent intensities, a plurality ofradiallyadjustable lamp sockets supporting said lamps,a plurality ofthumb screws controlling the adjustment of said lamp sockets, aninsulating block carrymg a plurality of contact points, each,pointconnected to the corresponding lamp socket, a spring contacttoicompleteany one of the plurality of lamp circuits, and a pivotal bracketsupporting said lamps and insulating block.

11. In a photographic printing machine of the type utilizing aconcentrated light source, the combination with a printing panel of apivotally mounted lamp bracket supporting a plurality of radiallyadjustable lamp sockets carrying a plurality of concentrated filamentlamps, each lamp having a different intensity, a pivotal support forsaid bracket, a series of thumb screws carried by the bracket, eachscrew controlling the adjustment of the corresponding socket to itsrelation thereto, an insulating block supporting a series of con tactpoints carried by the bracket, each contact point connected to a lampsocket and means to simultaneously bring one point at a time intooperative position with a spring contact and its corresponding lamp intooperative position for illuminating the printing panel, said springcontact being adapted to hold the bracket in said position.

12. In a photographic printing machine the combination with a printingpanel, of a source of light for said panel including a movably mountedlamp bracket, a plurality of lamps carried thereby, a plurality ofincomplete circuits including the lamps, and means tending to retain thebracket in a set position, said means also forming a switch forcompletting an incomplete circuit to a lamp.

13. In a photographic printing machine the combination with a printingpanel, of a source of light for said panel including a movably mountedlamp bracket, a plurality of lamps carried thereby, a plurality ofincom-' plete circuits including the lamps, and a spring arm adapted toresiliently engage Said bracket for locating the bracket and comtiletingone lamp circuit.

14. In a photographic printing machine the combination with a printingpanel, of a source of light for said panel including a movably mountedlamp bracket, a plurality of lamps carried thereby, a plurality ofincomplete circuits including the lamps and means tor completing onecircuit at a time including a pair oi cooperating contacts. one adaptedto enter into the other, said contacts serving as a sun p latch tendingto hold the bracket in a set position.

Signed at Rochester, New York, this 16th day of October, 1929.

m ROY S. HOPKINS.

